High vertical alignment (HVA), e.g., polymer stabilized vertical alignment (PSVA) is currently one of the mainstream techniques in the display panel industry (mainly including thin film transistor liquid crystal display (TFT-LCD), organic light emitting diode (OLED), and the like). This technique mainly takes advantage of the polymerization of macromolecules in liquid crystals under the combined action of ultraviolet and voltage, whereby automatic alignment of liquid crystals can be realized. Thus, when ultraviolet illuminates the liquid crystal panel, it is necessary to apply a certain amount of voltage to the liquid crystal panel, both ends of the liquid crystal, and both sides of the thin film transistor (TFT) and the color film (CF).
For this purpose, in the conventional method at present, some metal electric circuits are provided in a margin area of the TFT substrate. Through these metal electric circuits, external voltage can be transmitted into the liquid crystal panel. However, the liquid crystal panel at present is generally composed of two substrates, one above and one below, such as a CF substrate and a TFT substrate. In this case, a portion of the CF substrate will block the metal electric circuits at the TFT substrate so that the external voltage cannot be applied thereto. Consequently, this portion of the CF substrate is required to be cut off.
Currently, a single cutting machine is mainly used for cutting off said portion of the CF substrate in the industry, which is described as follows. In this method, the margin areas at two opposite sides (which may be one to four sides dependent on the design) of the liquid crystal panel motherboard are cut off by the single cutting machine, and metal wires of the TFT substrate to receive external voltage are exposed, so that external voltage can be applied thereto. Presently, the cutting-off process is usually divided into three steps, i.e. cutting, splintering and removing of end material. Cutting is to generate a crack of a certain depth on the surface of glass substrate. Splintering is to expand the crack generated under the action of force in order to achieve a smooth separation of the end material of glass. Then, vacuum absorption is used to hold the end material, which are subsequently removed from the TFT substrate and thus the metal electric circuits of the TFT substrate can be exposed, so that external voltage can be applied to them readily.
During removing the end material, sometimes it is difficult to split the end material from the TFT substrate. The wider the end material to be detached is, the harder the detachment will be, and the more likely the removal will fail. Investigations indicate that the reason could be as follows. The end material that needs to be detached is at one of two pieces of glass, while the other piece of glass does not need to be detached. Normally, the surfaces of the end material and the other piece of glass are both quite flat, and the two pieces of glass are fit to each other tightly after a force is applied thereon, with no air left between the two pieces of glass. Thus a vacuum environment is formed therebetween. Therefore, it is very difficult to remove one of the two pieces of glass under the external atmospheric pressure. In the meantime, the wider the end material, the more difficult the detachment is, and the higher the possibility of failure of the detachment is.